Power-driven letoff for looms



o. v. PAYNE June 10, I947.

' POWER nruvmu LET-OFF FOR LOOMS Filed Aug. 31, 1945 2 Sheets-Sheet l 0W1. fly? Ow-T/YMQ.

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June 10, 1947. o, v, PAYNE 2,421,961

POWERDRIVEN LET-OFF FOR LOOMS Filed .Aug. 31, 1945 2 Sheets-Sheet 2 Patented June 10, 1947 UNITED. STATES PATENT OFFICE h z.4z1.ae1"

rowan-maven m'rorr ron ooms Oscar V. Payna Leicester. Mala, assignor to Crompton J: Knowles Loom Works, Worcester, Mass, a corporation of. Massachusetts Application August 31, 1945,8eriai No. 613,910 4 6Claims. (o1. 139-:110)

This invention relates to improvements in warp letofl mechanisms for looms and it is the general object of the invention to provide means by which the warp beam can be turned by power to supply the warp consumed in the weaving operation.

The warp used in weaving is generally wound on a beam rotatably mounted at the back of the brake and an escapement device connected to the beam in such manner that forward movement of the whip roll due to increasing warp tension effects release of the brake so that the escapem'ent may operate and permit turning of the beam by a force-derived from the warp. It is an important object of my present invention to provide means by which the escapement device of such a letoif mechanism can be driven positively by power derived preferably from the loom.

The brake lever of the aforesaid letofi mechanism is released by the whip rollwhen the latter reaches a given forward position. It is another object of my present invention to provide driving mechanism between some part of the loom such ciated with my invention, the idler for-the driving belt being in non-driving position,

Fig. 2 is ,a plan view looking in the direction of arrow 2, Fig. 1, p rts being broken away,

Fig. 3 is an enlarged section on line 3-4 of Fig. 1, and

Fig. 4 is a reduced view similar to a part of Fig.

.1 but-showing the idler'pulley in driving position.

Referring particularly to Fig. 1, I have shown a loom frame it which supports a rearwardly extending bracket II having a bearing I2 receiving the gudgeon II at one end of the warp beam l4.

The warp W leads from the warp beam upwardly over a whip roll I5 mounted for rotation on a vertical lever l6 pivoted as at H with respect to as the bottom shaft and the escapement device the bracket ii. A lever [B is pivoted as at I! with respect to the bracket and has a laterally extending arm 20 which bears against the upright lever 16. A forwardly extending arm 2i of lever I8 is connected to a link 22 pivoted as at 22 to an upright arm 24 on weighted lever 25 pivoted as at 28 with respect to the bracket ll. Lever 25 is con-,

nected to a depending rod 21 the bottom of which has secured thereto a collar 28 engaging the under side of the forward arm 29 of a brake lever 30 pivoted as at 3| to the bracket I I.

- A brake shoe 32 pivoted to the rear arm 33 of brake lever 30 engages a friction brake surface 34 on an escapement lever 35 pivoted as at 38 to the bracket II and having stop arms 31 and 38 for engagement with a notched escapement wheel 29. The latter is fast with respect to a. pinion 40 and turns on a stud 4| supported by the bracket ll;

Pinion 40. meshes with a gear 42 turning with a pinion 43 rotatable on the bracket and meshing with a, gear 44 turning about the axis of lever 30.

A pinion 45 turns with gear 44 and meshes with a tightened by means of an idler pulley the position of which isdetermined by the brake lever. With such an arrangement the loom' will turn over without feeding warp so long as the warp tension is not too high, but as soon as the warp tension increases to a point requiring more warp the whip roll will effect rocking of the brake lever and the latter in turn will tighten the belt to transmit the turning force to the beam. As the beam turns under this force the warp slackens sufficiently to permit the whip roll to move rearwardly to a point v where the idler pulley returns to its normal position and the belt again slips without transmitting power to the beam, Yo

With these and other objects in view which will large gear 46 secured to the beam l4.

The'matter thus far described may be as set forth in more detailin my aforesaid patents and it is thought sufiicient for present purposes to state that when the whip roll is in, rearward position, a condition corresponding to relatively low tension of the warp, the rod 21 is depressed and a spring 50 surrounding it exerts-a downward force on arm 29 the effect of which is to hold the brake shoe 32 against the brake surface 34 and prevent rocking of the escapement lever 35. Un-

der "these conditions the warp beam is locked against rotation and as weaving continues the appear as the description proceeds, my invention ofl mechanism and driving part of the loom 8.8802 7 tion the escapement mechanism is free to rock and the-train of gearing already described will turn due to force derived from the warp and transmitted through the large gear 48. It is in this way that the escapement lever 35 is oscillated to permit a slight turning of the beam. As

will appear he:einafter, however, I provide additional means for turning the escapement wheel 39 so that in efl'ect the transmission of force through the train of gearing is reversed as to direction when compared with my prior previously mentioned patents.

The loom is provided with a bottom shaft 55 which ordinarily turns continuously durin loom operation in the direction of arrow a, Fig, 1, completing a rotation every second pick of the loom. The bottom shaft is in front'of the warp beam and has secured to it a large gear 56 which meshes with another gear not shown on the upper or crank shaft not shown of the loom.

15 In carying my invention into eifect I provide means by which the warp tension controls the transmission of power from the loom to the letofi", mechanism in such manner as to relieve the warp of the strain of transmitting all of the power required to turn the beam I4. This result I accomplish by securing a pulley 60 to the escapement wheel 39 as indicated in Fig. 2, the pulley having a hub 6| secured to a spider 62 which is fastened to the escapement wheel. A second and preferably smaller pulley 65 is secured as at 66 to cross arms 61 and 68 bolted as at 69 to the large gear 56 in such a way as to mount pulley 65 concentrically with the bottom shaft 55. A flexible belt 10 is then trained around the pulleys 60 and 65 as shown in Fig. 1 and is ordinarily slack enough so that pulley 65 can turn without causing turning of. pulley 60.

Arm 29 of the brake lever 30 has secured thereto a forwardly extending bar or the like having an upright arm 16 on which is rotatably mounted an idler pulley 11 positioned for engagement with the belt 10. The idler pulley is preferably close to the pulley 65 so that when raised from its normal position a considerable amount of the belt will be wrapped around with smaller forward pulley 65.

Under normal conditions, and assuming that the warp is sufiiciently slack to permit the whip roll l5 to assume a rearward position, the brake 32 will be against the escapement lever 35 and the warp beam will be held against rotation as already described. Under these conditions the bar 15 will be down as shown in Fig. 1 so that the idler pulley 11 will be in low position and will permit the belt 10 to run loosely without being able to transmit power from pulley 65 to pulley 60. This condition exists while the whip roll is in a rearward position, but as the whip roll moves forwardly, due to continued consumption of the warp, lever 30 will be rocked in a counter-clockwise direction as viewed in Fig. 1 and have two effects one of which is to move the brake 32 away from the escapement lever, thereby unlocking the warp beam so that it can be turned. The second effect of this rocking of lever 30'is to raise the idler pulley 'l'! to the position shown in Fig. 4, in which position the belt will be tightened sufficiently to transmit power from the driving pulley 65 to the driven pulley 60. Since the latter is secured to the escapement wheel 38 the train of gearing shown in Fig. 1 and previously described is set into motion for the purpose of rotating the gear 46 inthe direction of arrow b, Fig. 1, thereby causing the warp beam to turn in a, direction to supply warp.

The speed of the loom and the size of the pulleys 60 and 65 are such that under these conditions the warp beam will turn slightly faster than would otherwise be needed to supply the warp,

slackening the belt and arresting further input of power from the bottom shaft into the letoif mechanism. During loom operation the brake 32 is alternately on and ofi and the idler pulley TI is alternately ineffective and then efiective to cause the belt to transmit power from the bottom shaft to the letoff mechanism.

When the idler puley l1 rises to the position of Fig. 4 it moves the lower strand of the belt in engagement with the under side of the pulley 65, wrapping it somewhat around the latter, thereby not only tightening the belt but increasing the frictional engagement of it with the driving pulley. The vertical range of movement of the pulley 11 may be altered by reason of a slot 80 in the arm 16 and a screw or bolt 8| vertically adjustable in the slot 80 and serving asa pivot for the idler pulley.

From the foregoing it will be seen that I have provided a, simple form' of driving mechanism for a loom letoff wherein power from the bottom shaft of the loom is transmitted to the letoif escapement mechanism and from the latter to the warp beam in such direction as to turn the latter to supply warp. The whip roll l5 controls the brake as in my previous patents, but in addition also controls the position of the idler pulley l1, and the relationship is such that the brake is taken off when the belt is tightened, and is applied when the belt is slackened. The invention as set forth herein is of particular use with large beams'which are too heavy to be conveniently turned. by a force all of which is derived from the warp. It will be understood of course that when power is being transmitted from the bottom shaft to the letoff mechanism the whip roll is forward and the warp is under an increased tension and under these conditions the warp will add its force to that transmitted by the belt 10 to effect turning of the beam.

Having thus described my inventionit will be seen that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention and I do not wish to be limited to the details herein disclosed, but what I claim is: f

1. In letofi mechanism for a loom .having a regularly turning element and having a rotatably mounted warp beam, a whip roll over which the warp from the beam passes mounted to move to a forward position when warp tension is increasecland move to a rearward position when warp tension is reduced, a train of gearing connected to the beam, a pulley forming part of said train, a belt to transmit driving power from. said element to said pulley and normally slack to be ineffective to transmit power when the whip roll is in rearward position, and means controlled by the whip roll effective to tighten said lbelt when' said whip roll is in forward position for the purpose of transmitting force from the element through said pulley to said train to turn the warp beam in a direction toreduce warp tension.

2. In a loom having a rotating shaft and a rotatable warp beam supplying warp passing over a whip roll which is in forward position when the warp tension is relatively high and in rearward position when warp tension is relatively low, a train of gearing connected to the means, brake means in braking position to prevent said train and beam from turning when the whip roll is in rearward position, a pulley forming part of said train, a belt connecting said shaft and pulley and slack and ineffective to transmit force from the shaft to the pulley and train when the whip roll is in rearward position, and means controlled by the whip roll and operative when the latter moves forwardly to release said brake and simultaneously tighten said belt to cause the latter to turn the beam in a direction'to reduce'w p tension.

3. In a loom having a rotating shaft and a rotatable warp beam supplying warp which passes over a whip roll movable backwardly when warp tension is reduced and forwardly when warp tension is increased, a train of gearing connected to the beam, and including an escapement wheel, an oscillatable escapement lever controlling turning of the escapement wheel, a brake in brakin position to prevent oscillation of said lever and turning of said escapement wheel and gearing and beam when the whip roll is in rearward position, driving connections between said shaft and said escapement wheel idle, when the whip roll is in rearward position, and means operated by the whip roll when the latter moves forwardly to cause said brake to release said lever and simultaneously cause said driving connection to transmit force from the shaft to said escapement wheel and train to drive the beam in a direction to reduce warp tension.

4. 'In a loom having a rotating shaft and a, whip roll over which warp passes from arotatable warp beam, said whip roll moving from a rearward position toward a forward position when the tension of the warp is increased, a train of gearing connected to and turning with the beam, escapement mechanism including an oscillatable lever and escapement wheel operatively connected to the train of gearing, a brake in braking position when the whip roll is in rearward position to prevent turning of said escapement wheel and train of gearing and cause an increase in warp tension with resultant forward movement of the whip roll, normally idle power transmittin ,means between the shaft and the escapement wheel, and means effective when the whip roll 6 and causes the latter to move forwardly from a rearward position when tension in the warp increases, driving gearing for the beam, a brake for said driving gearing, a part rotating during loom operation, a belt between said part and gearing,

and connections between the whip roll, brake and i belt effective when the warp tension is relatively low and the whip roll is in rearward position to apply said brake to prevent turning of the gearing and cause said belt to be ineffective to transmit power from said part to said gearing and operative when the whip roll moves forwardly due to an increase in warp tension to release said brake and cause said belt to'transmit power from said part to said gearing for the purpose of turn-' ing the beam in a direction to reduce warp tension.

6. In a loom havinga rotatable warp beam supplying warp which passes over a whip roll which moves forwardly from a rearward position when forwardly due to increased warp tension to removes forwardly due to increase in tension to release said brake and simultaneously cause said force transmitting means to turn said escapement wheel and gearing in a direction to reduce warp tension by a force derived from the shaft.

5. In a loom having a, rotatable warp beam supplying warp which passes over a whip roll lease said brake and cause said driving mechanism to turn the escapement wheel and train of gearing in a direction to cause the warp beam topay off warp and reduce warp tension.

OSCAR V. PAYNE.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 2,184,059 Payne Dec. 19, 1939 513,867 B111 Jan. 30, 1894 2,394,161 Eiorentino Feb. 5, 1946 FOREIGN PATENTS Number I Country Date 320,092 France Aug. 9, 1902 3,848 Great Britain 1878 588,660 France Feb. 25 1925 

